There are several types of electric field-driven particles in the field of non-emissive displays. One class uses the so-called electrophoretic particle that is based on the principle of movement of charged particles in an electric field. In an electrophoretic receiver, the charged particles containing different reflective optical densities can be moved by an electric field to or away from the viewing side of the receiver, which produces a contrast in the optical density. Another class of electric field-driven particles are particles carrying an electric dipole. Each pole of the particle is associated with a different optical density (bi-chromatic). The electric dipole can be aligned by a pair of electrodes in two directions, which orient each of the two polar surfaces to the viewing direction. The different optical densities on the two halves of the particles thus produces a contrast in the optical densities.
To produce a high quality image it is essential to form a plurality of image pixels by varying the electric field on a pixel-wise basis. The electric fields can be produced by plural pairs of electrodes embodied in the receiver as disclosed in U.S Pat. No. 3,612.758. A shortcoming is that this solution requires the incorporation of electrodes in the receiver, increasing the receiver complexity.
Several features are needed in the above described non-emissive displays based on field-driven particles. It is desirable to reduce the writing time for producing an image on the display. It is also desirable for increasing the stability of the display after an image is produced.